Methods and apparatus for treating embolism

ABSTRACT

A device and method for intravascular treatment of an embolism, and particularly a pulmonary embolism, is disclosed herein. One aspect of the present technology, for example, is directed toward a clot treatment device that includes a support member having a plurality of first clot engagement members and second clot engagement members positioned about the circumference of a distal portion of the support member. In an undeployed state, individual first clot engagement members can be linear and have a first length, and individual second clot engagement members can be linear and have a second length that is less than the first length. The clot engagement members can be configured to penetrate clot material along an arcuate path and hold clot material to the clot treatment device.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application is a 35 U.S.C. 371 of International ApplicationNo. PCT/US2014/061645, filed Oct. 21, 2014, entitled “METHODS ANDAPPARATUS FOR TREATING EMBOLISM,” which claims the benefit of thefollowing applications:

(a) U.S. Provisional Patent Application No. 61/893,859, filed Oct. 21,2013;

(c) U.S. Provisional Patent Application No. 61/949,953, filed Mar. 7,2014;

(d) U.S. patent application Ser. No. 14/299,933, filed Jun. 9, 2014, nowU.S. Pat. No. 9,259,237, issued Feb. 16, 2016; and

(e) U.S. patent application Ser. No. 14/299,997, filed Jun. 9, 2014,which has been abandoned.

All of the foregoing applications are incorporated herein by referencein their entireties. Further, components and features of embodimentsdisclosed in the applications incorporated by reference may be combinedwith various components and features disclosed and claimed in thepresent application.

TECHNICAL FIELD

The present technology relates generally to devices and methods forintravascular treatment of emboli within a blood vessel of a humanpatient.

BACKGROUND

Thromboembolism occurs when a thrombus or blood clot trapped within ablood vessel breaks loose and travels through the blood stream toanother location in the circulatory system, resulting in a clot orobstruction at the new location. When a clot forms in the venouscirculation, it often travels to the lungs via the heart and lodgeswithin a pulmonary blood vessel PV causing a pulmonary embolism PE. Apulmonary embolism can decrease blood flow through the lungs, which inturn causes decreased oxygenation of the lungs, heart and rest of thebody. Moreover, pulmonary embolisms can cause the right ventricle of theheart to pump harder to provide sufficient blood to the pulmonary bloodvessels, which can cause right ventricle dysfunction (dilation), andheart failure in more extreme cases.

Conventional approaches to treating thromboembolism and/or pulmonaryembolism include clot reduction and/or removal. For example,anticoagulants can be introduced to the affected vessel to preventadditional clots from forming, and thrombolytics can be introduced tothe vessel to at least partially disintegrate the clot. However, suchagents typically take a prolonged period of time (e.g., hours, days,etc.) before the treatment is effective and in some instances can causehemorrhaging. Transcatheter clot removal devices also exist, however,such devices are typically highly complex, prone to cause trauma to thevessel, hard to navigate to the pulmonary embolism site, and/orexpensive to manufacture. Conventional approaches also include surgicaltechniques that involve opening the chest cavity and dissecting thepulmonary vessel. Such surgical procedures, however, come with increasedcost, procedure time, risk of infection, higher morbidity, highermortality, and recovery time. Accordingly, there is a need for devicesand methods that address one or more of these deficiencies.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present technology can be better understood withreference to the following drawings. The components in the drawings arenot necessarily to scale. Instead, emphasis is placed on illustratingclearly the principles of the present disclosure.

FIG. 1 is a side view of one embodiment of a clot treatment device in alow-profile or delivery state positioned in a blood vessel andconfigured in accordance with the present technology.

FIG. 2 is a side view of the clot treatment device shown in FIG. 1 in anunrestricted expanded or deployed state positioned in a blood vessel andconfigured in accordance with the present technology.

FIG. 3 is a partial side view of the clot treatment device shown in FIG.2 showing an isolated, deployed clot engagement member within anembolism.

FIG. 4 is a side view of a clot treatment device having distally-facingclot engagement members in a deployed state configured in accordancewith another embodiment of the present technology.

FIG. 5 is a side view of a clot treatment device having distally-facingclot engagement members in a deployed state configured in accordancewith another embodiment of the present technology.

FIG. 6 is a side perspective view of a clot treatment device in adeployed state configured in accordance with another embodiment of thepresent technology.

FIG. 7 is a side perspective view of a clot treatment device in adeployed state configured in accordance with another embodiment of thepresent technology.

FIG. 8 is a side perspective view of a portion of a clot treatmentdevice in a deployed state having a plurality of ports configured inaccordance with another embodiment of the present technology.

FIG. 9A is a front view of a portion of a delivery system for a clottreatment device that includes an expandable member in a deployed stateconfigured in accordance with an embodiment of the present technology.

FIG. 9B is a front view of a portion of a delivery system for a clottreatment device that includes an expandable member in a deployed stateconfigured in accordance with another embodiment of the presenttechnology.

FIG. 10A is a side view of an expandable member configured in accordancewith the present technology.

FIG. 10B is an end view of the expandable member shown in FIG. 10A.

FIG. 11A is a side cross-sectional view of a clot treatment deviceconfigured in accordance with the present technology.

FIG. 11B is an expanded, isolated view of a portion of the clottreatment device shown in FIG. 11A.

FIG. 12 is a pressure-generating member configured in accordance withthe present technology.

FIG. 13 is a schematic representation of the venous system of a humanleg.

FIG. 14 is an enlarged schematic representation of a deep veinthrombosis.

DETAILED DESCRIPTION

Specific details of several embodiments of clot treatment devices,systems and associated methods in accordance with the present technologyare described below with reference to FIGS. 1-14. Although many of theembodiments are described below with respect to devices, systems, andmethods for treating an embolism, other applications and otherembodiments in addition to those described herein are within the scopeof the technology. Additionally, several other embodiments of thetechnology can have different states, components, or procedures thanthose described herein. Moreover, it will be appreciated that specificelements, substructures, advantages, uses, and/or other features of theembodiments described with reference to FIGS. 1-14 can be suitablyinterchanged, substituted or otherwise configured with one another inaccordance with additional embodiments of the present technology.Furthermore, suitable elements of the embodiments described withreference to FIGS. 1-14 can be used as standalone and/or self-containeddevices. A person of ordinary skill in the art, therefore, willaccordingly understand that the technology can have other embodimentswith additional elements, or the technology can have other embodimentswithout several of the features shown and described below with referenceto FIGS. 1-14.

With regard to the terms “distal” and “proximal” within thisdescription, unless otherwise specified, the terms can reference arelative position of the portions of a clot treatment device and/or anassociated delivery device with reference to an operator and/or alocation in the vasculature.

I. SELECTED EMBODIMENTS OF CLOT TREATMENT DEVICES

FIG. 1 is a side view of one embodiment of a clot treatment device 200(“the device 200”) in a low-profile or delivery state positioned in ablood vessel V, and FIG. 2 is a side view of the device 200 in anunrestricted expanded or deployed state that is well suited for removingclot material from a blood vessel (e.g., a pulmonary blood vessel).Referring to FIGS. 1 and 2 together, the device 200 can include asupport member 204 and a plurality of treatment portions (referred tocollectively as treatment portions 203, referred to individually asfirst-fourth treatment portions 203 a-d, respectively) spaced apartalong the support member 204. Each treatment portion 203 can include ahub 206 positioned around the support member 204 and a plurality of clotengagement members 202 integral with and extending distally from thecorresponding hub 206 to a distal free end 205. As such, individualtreatment portions 203 can include a plurality of clot engagementmembers 202 positioned about the circumference of the support member204. Although four treatment portions 203 are shown in FIGS. 1 and 2, inother embodiments the clot treatment device can include more or fewerthan four treatment portions 203 (e.g., two treatment portions, threetreatment portions, five treatment portions, etc.).

In the delivery state shown in FIG. 1 the clot engagement members 202can be generally linear and extend generally parallel to the supportmember 204. The distal ends 205 of the clot engagement members 202 areaccordingly the distal-most portion of the clot engagement members 202in the delivery state. In the expanded state, as shown in FIG. 2, theclot engagement members 202 can project radially outwardly relative tothe support member 204 in a curved shape. The clot engagement members202 can have a proximally facing section 212 which defines a proximallyfacing concave portion, and, in some embodiments, the clot engagementmembers 202 can further include an end section 214 that curves radiallyinwardly from the proximally facing section 212. When deployed within ablood vessel adjacent to clot material, the clot engagement members 202are configured to penetrate the clot material along an arcuate path andhold clot material to the device 200.

In some embodiments the treatment portions 203 can be fabricated from asingle tube (e.g., a hypotube). A plurality of elongated slits may becut or machined through the wall of the tube by various means known inthe art (e.g., conventional machining, laser cutting, electricaldischarge machining, photochemical machining, etc.) to form a pluralityof clot engagement members 202 that are integral with the correspondinghub 206. In some embodiments, the tube can be cut such that individualclot engagement members 202 can have non-circular cross-sections. Thecut tube may then be formed by heat treatment to move from the deliverystate shown in FIG. 1 to the deployed state shown in FIG. 2 in which thearcuate clot engagement members 202 project radially outward. As isknown in the art of heat setting, a fixture or mold may be used to holdthe structure in its desired final configuration and subjected to anappropriate heat treatment such that the clot engagement members 202assume or are otherwise shape-set to the desire arcuate shape. In someembodiments, the device or component may be held by a fixture and heatedto about 475-525° C. for about 5-15 minutes to shape-set the structure.In some embodiments, the treatment portions 203 can be formed fromvarious metals or alloys such as Nitinol, platinum, cobalt-chromealloys, 35N LT, Elgiloy, stainless steel, tungsten or titanium.

Referring still to FIGS. 1-2, the clot engagement members 202 ofdifferent treatment portions 203 can have different lengths (referred tocollectively as L, referred to individually as first-fourth lengthsL_(a)-L_(b)) in the delivery state (FIG. 1) and thus can extenddifferent distances D from the support member 204 in the deployed state(FIG. 2). As such, deployment of the clot engagement members 202self-centers the device within the blood vessel V and forces thestiffer, shorter clot engagement members 202 to be positioned radiallyfarther from the vessel wall V. As used herein, “shorter clot engagementmembers” or “shorter treatment portions” refers to clot engagementmembers 202 and/or treatment portions 203 with lesser lengths L and/ordistances D relative to the other clot engagement members 202 and/ortreatment portions 203 of the same clot treatment device, and “longerclot engagement members” or “longer treatment portions” refers to clotengagement members 202 and/or treatment portions 203 with greaterlengths L and/or distances D relative to the other clot engagementmembers 202 and/or treatment portions 203 of the same clot treatmentdevice.

For example, as shown in FIG. 1, in the delivery state, the firsttreatment portion 203 a can have clot engagement members with a firstlength L_(a), the second treatment portion 203 b can have clotengagement members 202 with a second length L_(b), the third treatmentportion 203 c can have clot engagement members 202 with a third lengthL_(c), and the fourth treatment portion 203 d can have clot engagementmembers 202 with a fourth length L_(d). In FIG. 1, the clot engagementmember lengths L of adjacent treatment portions 203 alternate betweenshorter and longer clot engagement members (i.e., clot engagementmembers 202 of first and third treatment portions 203 a, 203 c alternatewith clot engagement members 202 of the second and fourth treatmentportions 203 b, 203 d along the support member 204). In other words, inthe embodiment shown in FIG. 1, the first length L_(a) is less than thesecond length L_(b), the second length L_(b) is greater than the thirdlength L_(c), and the third length L_(c) is less than the fourth lengthL_(d). In other embodiments, the clot treatment device 200 and/ortreatment portions 203 can have other suitable configurations and/orarrangements. For example, the clot treatment device 200 can include anyarrangement of treatment portions 203 having shorter clot engagementmembers 202 and treatment portions 203 having longer clot engagementmembers 202 relative to the shorter clot engagement members 202.Moreover, the clot treatment device 200 can have any number of treatmentportions 203 having shorter clot engagement members 202 and/or anynumber of treatment portions 203 having longer clot engagement members202. Also, clot engagement members 202 having varying lengths need notbe in separate treatment portions 203. For example, in some embodiments,one or more treatment portions 203 can include both shorter and longerclot engagement members 202 in the same treatment portion 203.

Referring to FIG. 2, in the deployed state, the clot treatment device200 can include a first treatment portion 203 a having clot engagementmembers 202 with a radially furthest apex 216 a that is a first distanceD_(a) from the support member 204, a second treatment portion 203 bhaving clot engagement members 202 with a radially furthest apex 216 bthat is a second distance D_(b) from the support member 204, a thirdtreatment portion 203 c having clot engagement members 202 with aradially furthest apex 216 c that is a third distance D_(c) from thesupport member 204, and a fourth treatment portion 203 d having clotengagement members 202 with a radially furthest apex 216 d that is afourth distance D_(d) from the support member 204. As shown in FIG. 2,the distance D of the radially furthest apex of adjacent treatmentportions 203 from the support member 204 can alternate between shorter(clot engagement members 202 of first and third treatment portions 203a, 203 c) and longer (clot engagement members 202 of the second andfourth treatment portions 203 b, 203 d). In other words, in theembodiment shown in FIG. 1, the first distance D_(a) is less than thesecond distance D_(b), the second distance D_(b) is greater than thethird length D_(c), and the third distance D_(c) is less than the fourthdistance D_(d). In other embodiments, the clot treatment device 200and/or treatment portions 203 can have other suitable configurationsand/or arrangements. For example, the clot treatment device 200 caninclude any arrangement of treatment portions 203 having clot engagementmembers 202 with longer or shorter radially furthest apex distances D.Moreover, the clot treatment device 200 can have any number of treatmentportions 203 having shorter clot engagement member radially furthestapex distances D and/or any number of treatment portions 203 havinglonger clot engagement members radially furthest apex distances D. Also,clot engagement members 202 having varying radially furthest apexdistances D need not be in separate treatment portions 203. For example,in some embodiments, one or more treatment portions 203 can includeengagement members 202 with both shorter radially furthest apexdistances D and longer radially further apex distances D.

Advantageously, clot engagement members 202 having shorter radiallyfurthest apex distances D and/or shorter lengths L can have a greaterradial stiffness than clot engagement members 202 having longer radiallyfurthest apex distances D and/or longer lengths L. As shown in theisolated side view of a clot engagement member of FIG. 3, when deployed,the shorter, stiffer clot engagement members 202 can thus be spacedapart from the vessel wall V and grasp a more central portion of theclot material to provide mechanical resilience during withdrawal of theclot material CM while the apices of the longer, more flexible clotengagement members 202 (not shown in FIG. 3) atraumatically engage andslide along the vessel wall V. In some embodiments, the stiffness of theshorter clot engagement members 202 may be from about 150% to about 400%greater than the stiffness of the longer clot engagement members 202. Insome embodiments, the type of material, cross-sectional shape and/orarea of the individual clot engagement members 202 can also be varied toaffect the radial stiffness of the clot engagement members 202. Forexample, the relatively shorter clot engagement members 202 can be madefrom a first material and the relatively longer clot engagement members202 can be made from a second material that is more ductile, elastic,and or flexible than the first material, and/or the shorter clotengagement members 202 can have a great cross-sectional thickness orarea than the relatively longer clot engagement members 202.

The clot engagement members 202 can have a single or constant radius ofcurvature. In other embodiments, the clot engagement members 202 canhave a plurality of radii of curvature, such as a first region with afirst radius of curvature and a second region with a second radius ofcurvature. In some embodiments, the clot engagement members 202 can havea single radius of curvature that is the same for all of the clotengagement members 202. In other embodiments, the clot treatment device200 can have a first group of clot engagement members 202 with aconstant radius of curvature and a second group of clot engagementmembers 202 with a plurality of radii of curvature. Moreover, inadditional embodiments the clot treatment device 200 can include a firstgroup of clot engagement members 202 having a first radius of curvatureand a second group of clot engagement members 202 having a second radiusof curvature different than the first radius of curvature. In someembodiments, the radius of the clot engagement members 202 can bebetween about 1.5 mm and about 12 mm, and in some embodiments, betweenabout 2 mm and about 12 mm.

FIG. 4 is a side view of another embodiment of a clot treatment device400 in a deployed state configured in accordance with the presenttechnology. As shown in FIG. 4, the clot treatment device 400 caninclude a support member 404 and a plurality of clot engagement members402 positioned about the support member 404. The support member 404 canbe an elongated tubular structure that includes a lumen configured toslidably receive a guidewire GW therethrough. As shown in FIG. 4, in thedeployed state, the clot engagement members 402 can extend radiallyoutward from the support member 404 and curve distally such thatindividual clot engagement members 402 include a concave,distally-facing portion 411.

The clot engagement members 402 can be arranged in rows such thatadjacent rows along the support member 404 alternate between long 407and short 409 clot engagement members. Additionally, the short clotengagement members 409 can be circumferentially aligned with the long407 clot engagement members 407 about the support member 404. In otherembodiments, the clot engagement members 402 can have other suitablearrangements and/or configurations. For example, in some embodiments,one or more of the short clot engagement members 409 can becircumferentially offset from one or more of the long clot engagementmembers 409 about the support member 404, the long and short clotengagement members 407, 409 can be within the same rows, additionally oralternatively arranged in columns, and/or randomly positioned along orabout the support member 404.

FIG. 5 is a side view of another embodiment of a clot treatment device500 in a deployed state configured in accordance with the presenttechnology. As shown in FIG. 5, the clot treatment device 500 caninclude an expandable mesh 505 and a plurality of arcuate clotengagement members 502 extending radially outwardly from the expandablemesh 505. Although only distally-facing clot engagement members 502 areshown in FIG. 5, in other embodiments, the clot treatment device 500 canadditionally or alternatively include proximally-facing clot engagementmembers (such as those shown in FIGS. 1-2 and FIG. 3). In someembodiments, the clot engagement members 502 can be interwoven into themesh structure 505. In other embodiments, the clot engagement members502 can also be bonded, soldered, welded, tied or otherwise securedand/or mechanically interlocked to the mesh 505.

In certain procedures, it may be advantageous to move the clot treatmentdevice along the vessel (fully or partially within the embolism) in boththe upstream and downstream directions to facilitate engagement and/ordisruption of a clot or thrombus by the clot engagement members. Duringsuch procedures, it may be advantageous to include one or moredistally-facing clot engagement members to enhance engagement and/ordisruption of the clot material. Accordingly, the clot treatment devicesof the present technology can include both proximally-facing clotengagement members and distally-facing clot engagement members. Forexample, FIG. 6 is a perspective side view of a portion of a clottreatment device 600 having proximally-facing (e.g., concave proximally)treatment portions 603 p (collectively referred to as treatment portions603) comprised of proximally-facing 602 p clot engagement members anddistally-facing (e.g., concave distally) treatment portions 603 dcomprised of distally-facing 602 d clot engagement members. As shown inFIG. 6, the distally-facing clot engagement members 602 d of thedistally-facing treatment portions 603 d extend radially outwardly fromthe corresponding hub 606, then curve distally to a distal free-end.Although the clot treatment device 600 shown in FIG. 6 includes twodistally-facing treatment portions 603 d and two proximally-facingtreatment portions 603 p along the support member 604, the clottreatment device 600 can include any arrangement and/or configuration oftreatment portions and/or clot engagement members. For example, as shownin the clot treatment device 700 of FIG. 7, the adjacent treatmentportions can alternate between those including proximally-facing clotengagement members 702 p and distally-facing clot engagement members 703d.

FIG. 8 is a side perspective view of a portion of another embodiment ofa clot treatment device 800 configured in accordance with the presenttechnology. As shown in FIG. 8, the support member 804 of the clottreatment device 800 can include holes or ports 805 to allow theinfusion of fluids (e.g., thrombolytics) along its length and betweentreatment portions (labeled 802 a and 802 b). The ports 805 can bepositioned anywhere along the length of the support member 804 (e.g.,proximal to the proximal-most treatment portion, distal to thedistal-most treatment portion, in between treatment portions, etc.). Thelocation of the ports 805 along the length of the support member 804 canenhance the direct infusion of the fluids into the clot and improve thebiologic action and effectiveness of such drugs. Additionally, in someembodiments, the clot engagement members can be at least partiallyhollow and/or include ports or inlets along their lengths and/or attheir free-ends.

II. ADDITIONAL EMBODIMENTS OF CLOT TREATMENT DEVICES AND ASSOCIATEDDEVICES, SYSTEMS AND METHODS

FIG. 9 is a front view of a delivery system 900 for use with the clottreatment devices of the present technology. As shown in FIG. 9, thedelivery system 900 can include a guide-catheter 902 and an expandablemember 904 (e.g., a balloon) coupled to a distal portion of theguide-catheter 902. In such embodiments, the expandable member 904 canbe expanded to a diameter less than the vessel diameter, as shown inFIG. 9. Use of the expandable member 904 coupled to the distal portionof the guide catheter 902 can divert flow in the vessel away from thedistal portion of the guide catheter 902, thereby reducing oreliminating the possibility of clot material traveling proximal of thedevice during retraction of the clot treatment device 910 (and adherentclot) into the guide catheter 902 (shown in FIG. 9B). Moreover, the useof an expandable member 904 with the guide catheter 902 can beadvantageous as the expandable member 904 can form a funnel adjacent tothe distal end of the guide catheter 904, thereby facilitatingretraction of the clot material into the guide catheter 904.Additionally, expanding the expandable member 904 to a diameter that isless than the diameter allows some blood flow BF to occur through thevessel near the treatment site, thus reducing any risk associated withcomplete blockage of blood flow.

FIG. 10A is a side view of a portion of a delivery system 1000 for usewith the clot treatment devices of the present technology, and FIG. 10Bis a top view of the delivery system shown in FIG. 10A. Referring toFIGS. 10A and 10B together, in those embodiments that include expandablemembers coupled to a distal portion of the guide catheter, theexpandable member can center the guide catheter within the vessel,thereby enhancing and/or facilitating clot removal and/or aspiration.Since the clot treatment device is self-expanding, it will generallytend to self-center within the blood vessel in addition to the centeringof the guide catheter enabled by the expandable members of the deliverysystem. Alignment of the guide catheter and clot treatment device willprovide the best situation for guiding of clot to the distal end of thecatheter with the least amount of shearing of clot by the distal end ofthe catheter. Thus, general alignment of the clot treatment device andthe guide catheter may improve the efficiency and quality of clotextraction and/or clot aspiration and thereby reduce breakup of the clotand distal embolization. In some embodiments, a multi-lobed expandablemember may be used to center the guide catheter within the blood vesselwhile allowing some blood flow past the expandable members so as to notcompletely occlude the blood vessel during the procedure. Variousmulti-lobed expandable member configurations are known in the artincluding but not limited to a tri-lobed expandable member as shown inFIGS. 10A and 10B.

In any of the clot treatment device embodiments that comprise a centraltube member, the inner tube or “tether tube” may be constructed so as tohave spring properties. For example, as shown in FIGS. 11A and 11B, thetube may be a coil or spiral cut tube so that when tension is applied,it readily elongates. A spring inner tube member may provide improvedself-expansion while still providing a lumen for a guidewire, catheteror the like to be inserted therethrough. Moreover, the inner tube or“tether tube” may be constructed with a first proximal tube that isattached to the clot treatment device proximal to the radially expandingsegment and a second distal tube that is attached to the clot treatmentdevice distal to the radially expanding segment. One tube may be largerin diameter than the other so that they may be over-lapped with aportion where the smaller tube is coaxial within the larger tube andthus “telescoped” as shown in FIGS. 11A and 11B. In this telescopedconfiguration, the tubes may slide freely relative to each other. Thus,with a telescoped inner tube configuration, a guidewire lumen ismaintained while allowing a large elongation without plasticdeformation.

Now referring to FIG. 12, in some embodiments, parts of the system thatretract and/or aspirate fluid and debris may be automated. For example,the movement of the pump (e.g. syringe) plunger may have a mechanismsuch as a linear actuator, drive screw or the like to effect movementunder electronic control. Likewise, the linear movement of the deviceand delivery catheter for deployment and/or retraction may also beoperated by a mechanism. In some embodiments, both the pump and thecatheter and device movements may be mechanized and synchronized. Inaddition, sensors may be incorporated into the system on either thedevice and/or catheters such that the system will automatically turnmechanisms on/off as desired. This automation may be further controlledby a programmable controller, computer or electronics and software as iswell-known in the art of automation. In some embodiments, the system mayautomatically shut off aspiration when a predetermined amount of deviceretraction has taken place. That way, the amount of blood that isaspirated is limited. In some embodiments, a continuously aspiratingpump mechanism rather than the discrete pump (e.g. syringe) as describedherein may be used. The use of a foot petal, a hand switch or anautomated or sensor actuated control to limit the duration of acontinuous pump may allow smooth continuous aspiration during deviceretraction without excessive blood being removed from the patient. Thismay be accomplished by having the pump operate for a relatively shortduration or pulses. In some embodiments, the pump may operate for lessthan about 15 seconds and in other embodiments less that about 5seconds. A diagram of such a system with a continuous aspiration pump isshown in Figure F. In some embodiments, a method of synchronized deviceretraction and aspiration is described wherein less than about 500 cc ofblood and debris are removed from the patient. In other embodiments, thedevice may be retracted with aspiration of between about 50 cc and 400cc, in some embodiments less than about 200 cc and in some embodimentsless than about 100 cc of blood and debris.

III. PERTINENT ANATOMY AND PHYSIOLOGY

Some embodiments described here may be particularly useful for thetreatment of deep vein thrombosis. (See FIGS. 13 and 14). Deep veinthrombosis (DVT) is a medical condition that results from the formationof a blood clot, or thrombus, within a vein. Thrombi may develop in theveins of the calves, legs, arms, pelvis or abdomen, but they may occurin other locations as well. The clot is typically formed from a poolingof blood within the vein due to abnormally long periods of rest orinactivity, e.g. when an individual is bed ridden following surgery orsuffering a debilitating illness or during extended airline flights. Thepropensity to form clots can be also be influenced by other factorsincluding, coagulation disorders, the presence of cancer, dehydration,hormone replacement therapy, use of birth control pills, geneticdeficiencies, autoimmune disorders, and endothelial cell injury andtrauma, etc. Thrombi are likely to form at the location of a stenosis(e.g., an unnatural narrowing of an artery). Clots often form near thevenous valves; one-way valves that prevent the back-flow of blood as itreturns to the right heart (blood is squeezed up the leg against gravityand the valves prevent it from flowing back to our feet). Clinicalsequelae of DVT are significant in both the acute and chronic settings.Initial consequences include acute lower-extremity symptoms, risk ofpulmonary emboli (PE) and death. Long-term consequences includerecurrent DVT, lower-extremity venous hypertension, claudication, pain,swelling and ulceration, which can result in significant post-thromboticmorbidity. Potentially thromboembolic DVT usually arises in one of thelarge deep veins of the lower limb (e.g. iliac and femoral veins).Patients with iliofemoral DVT tend to have marked pain and swelling andup to 50% experience pulmonary embolism.

Percutaneous access for endovascular interventions is most oftenachieved in the vein distal to the occluded segment. For isolated iliacDVT, an ipsilateral common femoral puncture is most appropriate.Alternatively, a retrograde approach from either the jugular, iliac veinor the contralateral femoral vein may be used for isolated iliac andfemoral vein DVT. More commonly, however, patients present with moreextensive iliofemoral or iliofemoral popliteal thrombosis, in which caseaccess is best obtained from the ipsilateral popliteal vein while thepatient is positioned prone. Ultrasound guidance may be used for accessof the popliteal or tibial veins and for any access obtained while thepatient is fully anticoagulated. Further, a micropucture technique witha 22-gauge needle and 0.014-inch guidewire may minimize bleedingcomplications and vessel wall trauma. Following initial access, thethrombus is crossed with a guidewire to facilitate catheter or devicepositioning. For a lower puncture location (i.e., closer to the feet)such as the popliteal, a suitable (e.g., less than 10 F) catheterintroducer sheath (such as a Flexor® manufactured by Cook, Inc. ofBloomington, Ind.) may be introduced into the vein over a guidewire. Ifalternate access is done for a retrograde approach to the thrombosis, alarger introducer (up to about 22 F) may be used. If a downstream accessis made and then a retrograde approach to the thrombus is done, anexpandable tip catheter such as that shown in FIGS. 20 and 21(PCT/US13/61470) may help prevent clot or debris that may be dislodgedor embolized during the procedure from traveling toward the heart.Alternatively, if a lower or upstream access to the vein and thenantegrade approach to the thrombus is made, an occlusion device such asa balloon or a filtration/capture device such a distal protection devicemay be place downstream of the thrombus. For example, a distalprotection device may inserted into the iliac or IVC for a contralateralvein. An exemplary distal protection device is the SpiderFX™ EmbolicProtection Device commercially available from Covidien (Plymouth,Minn.).

IV. EXAMPLES

The following examples are illustrative of several embodiments of thepresent technology:

1. A clot treatment device for treating an embolism within a bloodvessel, the clot treatment device comprising:

-   -   a support member configured to extend through a delivery        catheter, wherein the support member has a proximal portion and        a distal portion;    -   a plurality of first clot engagement members positioned about        the circumference of the distal portion of the support member,        wherein, in the deployed state, individual first clot engagement        members extend radially outwardly with respect to the support        member and have a curved portion that includes a first radially        furthest apex that extends a first radial distance from the        support member;    -   a plurality of second clot engagement members positioned about        the circumference of the distal portion of the support member,        wherein, in the deployed state, individual second clot        engagement members have a curved portion that includes a second        radially furthest apex that extends a second radial distance        from the support member, and wherein the first radial distance        is greater than the second radial distance;    -   wherein, in the deployed state, individual curved portions of        the first and second clot engagement members project radially        outwardly relative to the support member in a curve that has a        proximally extending section which defines a proximally facing        concave portion, and wherein the curved portion of the first and        second clot engagement members further includes an end section        that curves radially inwardly from the proximally extending        section; and    -   wherein the clot engagement members are configured to penetrate        clot material along an arcuate path and hold clot material to        the clot treatment device.

2. The clot treatment device of example 1, further comprising:

-   -   a first hub positioned around the support member at a first        location; and    -   a second hub positioned around the support member at a second        location spaced apart from the first location along the support        member;    -   wherein—        -   individual first clot engagement members extend from the            first hub, wherein a proximal portion of the first clot            engagement members are integral with the first hub; and        -   individual second clot engagement members extend from the            second hub, wherein a proximal portion of the second clot            engagement members are integral with the second hub.

3. The clot treatment device of any of examples 1 or 2 wherein:

-   -   at least one of the first radially furthest apices of the        individual first clot engagement members are configured to        engage the vessel wall in a deployed state; and    -   none of the second radially furthest apices of the individual        first clot engagement members are configured to engage the        vessel wall in a deployed state.

4. The clot treatment device of any of examples 1-3 wherein the firstclot engagement members have a first stiffness and the second clotengagement members have a second stiffness greater than the firststiffness.

5. The clot treatment device of any of examples 1-4 wherein:

-   -   the first clot engagement members are positioned about the        support member at a first location along the length of the        support member; and    -   the second clot engagement members are positioned about the        support member at a second location along the length of the        support member that is spaced longitudinally apart from the        first location along the support member.

6. The clot treatment device of any of examples 1-5, further comprising:

-   -   a plurality of third clot engagement members positioned about        the circumference of the distal portion of the support member,        wherein, in the deployed state, individual third clot engagement        members extend radially outwardly with respect to the support        member and have a curved portion that includes a third radially        furthest apex that extends a third radial distance from the        support member; and    -   wherein the third radial distance is substantially the same as        the first radial distance.

7. The clot treatment device of example 6, further comprising:

-   -   a plurality of fourth clot engagement members positioned about        the circumference of the distal portion of the support member,        wherein, in the deployed state, individual fourth clot        engagement members extend radially outwardly with respect to the        support member and have a curved portion that includes a fourth        radially furthest apex that extends a fourth radial distance        from the support member; and    -   wherein the fourth radial distance is substantially the same as        the second radial distance.

8. The clot treatment device of example 7 wherein:

-   -   the first clot engagement members are positioned at a first        location along the length of the support member;    -   the second clot engagement members are positioned at a second        location along the length of the support member that is        different than the first location;    -   the third clot engagement members are positioned at a third        location along the length of the support member that is        different than the first and second locations;    -   the fourth clot engagement members are positioned at a fourth        location along the length of the support member that is        different than the first, second, and third locations.

9. The clot treatment device of any of examples 1-5 and 7, furthercomprising:

-   -   a plurality of third clot engagement members positioned about        the circumference of the distal portion of the support member,        wherein, in the deployed state, individual third clot engagement        members extend radially outwardly with respect to the support        member and have a curved portion that includes a third radially        furthest apex that extends a third radial distance from the        support member; and    -   wherein the third radial distance is different than the second        radial distance and the first radial distance.

10. The clot treatment device of any of examples 1-5 and 7, furthercomprising:

-   -   a plurality of third clot engagement members positioned about        the circumference of the distal portion of the support member,        wherein, in the deployed state, individual third clot engagement        members extend radially outwardly with respect to the support        member and have a curved portion that includes a third radially        furthest apex that extends a third radial distance from the        support member; and    -   wherein, in the deployed state, individual curved portions of        the third engagement members project radially outwardly relative        to the support member in a curve that has a distally extending        section which defines a distally facing concave portion, and        wherein the curved portion of individual third engagement        members further includes an end section that curves radially        inwardly from the distally extending section.

11. A treatment device for treating an embolism within a blood vessel,the clot treatment device moveable between a low-profile undeployedstate and a deployed state, the clot treatment device comprising:

-   -   a support member configured to extend through a delivery        catheter, wherein the support member has a proximal portion and        a distal portion;    -   a plurality of first clot engagement members positioned about        the circumference of the distal portion of the support member,        wherein, in the undeployed state, individual first clot        engagement members are linear and have a first length;    -   a plurality of second clot engagement members positioned about        the circumference of the distal portion of the support member,        wherein, in the undeployed state, individual second clot        engagement members are linear and have a second length that is        less than the first length;    -   wherein, in the deployed state, the individual first and second        clot engagement members project radially outwardly relative to        the support member in a curve that has a proximally extending        section which defines a proximally facing concave portion, and    -   wherein the clot engagement members are configured to penetrate        clot material along an arcuate path and hold clot material to        the clot treatment device.

12. The clot treatment device of example 11 wherein the curved portionfurther includes an end section that curves radially inwardly from theproximally extending section.

13. The clot treatment device of any of examples 11-12 wherein, in theundeployed state:

-   -   individual first clot engagement members are positioned parallel        to the support member; and individual second clot engagement        members positioned parallel to the support member.

14. The clot treatment device of any of examples 11-13, furthercomprising:

-   -   a first hub positioned around the support member at a first        location; and    -   a second hub positioned around the support member at a second        location spaced apart from the first location along the support        member;    -   wherein—        -   individual first clot engagement members extend distally            from the first hub in the undeployed state, wherein a            proximal portion of the first clot engagement members are            integral with the first hub; and        -   individual second clot engagement members extend distally            from the second hub in the undeployed state, wherein a            proximal portion of the second clot engagement members are            integral with the second hub.

VI. CONCLUSION

The above detailed descriptions of embodiments of the present technologyare for purposes of illustration only and are not intended to beexhaustive or to limit the present technology to the precise form(s)disclosed above. Various equivalent modifications are possible withinthe scope of the present technology, as those skilled in the relevantart will recognize. For example, while steps may be presented in a givenorder, alternative embodiments may perform steps in a different order.The various embodiments described herein and elements thereof may alsobe combined to provide further embodiments. In some cases, well-knownstructures and functions have not been shown or described in detail toavoid unnecessarily obscuring the description of embodiments of thepresent technology.

From the foregoing, it will be appreciated that specific embodiments ofthe technology have been described herein for purposes of illustration,but well-known structures and functions have not been shown or describedin detail to avoid unnecessarily obscuring the description of theembodiments of the technology. Where the context permits, singular orplural terms may also include the plural or singular term, respectively.

Certain aspects of the present technology may take the form ofcomputer-executable instructions, including routines executed by acontroller or other data processor. In some embodiments, a controller orother data processor is specifically programmed, configured, and/orconstructed to perform one or more of these computer-executableinstructions. Furthermore, some aspects of the present technology maytake the form of data (e.g., non-transitory data) stored or distributedon computer-readable media, including magnetic or optically readableand/or removable computer discs as well as media distributedelectronically over networks. Accordingly, data structures andtransmissions of data particular to aspects of the present technologyare encompassed within the scope of the present technology. The presenttechnology also encompasses methods of both programmingcomputer-readable media to perform particular steps and executing thesteps.

Moreover, unless the word “or” is expressly limited to mean only asingle item exclusive from the other items in reference to a list of twoor more items, then the use of “or” in such a list is to be interpretedas including (a) any single item in the list, (b) all of the items inthe list, or (c) any combination of the items in the list. Additionally,the term “comprising” is used throughout to mean including at least therecited feature(s) such that any greater number of the same featureand/or additional types of other features are not precluded. It willalso be appreciated that specific embodiments have been described hereinfor purposes of illustration, but that various modifications may be madewithout deviating from the technology. Further, while advantagesassociated with certain embodiments of the technology have beendescribed in the context of those embodiments, other embodiments mayalso exhibit such advantages, and not all embodiments need necessarilyexhibit such advantages to fall within the scope of the technology.Accordingly, the disclosure and associated technology can encompassother embodiments not expressly shown or described herein.

We claim:
 1. A clot treatment device for treating an embolism within a blood vessel, the clot treatment device comprising: a support member configured to extend through a delivery catheter, wherein the support member has a proximal portion and a distal portion; a plurality of first clot engagement members positioned about the circumference of the distal portion of the support member, wherein, in deployed state, individual first clot engagement members extend radially outwardly with respect to the support member and have a curved portion that includes a first radially furthest apex that extends a first radial distance from the support member; a plurality of second clot engagement members positioned about the circumference of the distal portion of the support member, wherein, in the deployed state, individual second clot engagement members have a curved portion that includes a second radially furthest apex that extends a second radial distance from the support member, and wherein the first radial distance is greater than the second radial distance; wherein, in the deployed state, individual curved portions of the first and second clot engagement members project radially outwardly relative to the support member in a curve that has a proximally extending section which defines a proximally facing concave portion, and wherein the curved portion of the first and second clot engagement members further includes an end section that curves radially inwardly from the proximally extending section; wherein the first clot engagement members have a first stiffness and the second clot engagement members have a second stiffness greater than the first stiffness, and wherein the clot engagement members are configured to penetrate clot material along an arcuate path and hold clot material to the clot treatment device.
 2. The clot treatment device of claim 1, further comprising: a first hub positioned around the support member at a first location; and a second hub positioned around the support member at a second location spaced apart from the first location along the support member; wherein— individual first clot engagement members extend from the first hub, wherein a proximal portion of the first clot engagement members are integral with the first hub; and individual second clot engagement members extend from the second hub, wherein a proximal portion of the second clot engagement members are integral with the second hub.
 3. The clot treatment device of claim 1 wherein: at least one of the first radially furthest apices of the individual first clot engagement members are configured to engage the vessel wall in the deployed state; and none of the second radially furthest apices of the individual second clot engagement members are configured to engage the vessel wall in the deployed state.
 4. The clot treatment device of claim 1 wherein: the first clot engagement members are positioned about the support member at a first location along the length of the support member; and the second clot engagement members are positioned about the support member at a second location along the length of the support member that is spaced longitudinally apart from the first location along the support member.
 5. The clot treatment device of claim 1, further comprising: a plurality of third clot engagement members positioned about the circumference of the distal portion of the support member, wherein, in the deployed state, individual third clot engagement members extend radially outwardly with respect to the support member and have a curved portion that includes a third radially furthest apex that extends a third radial distance from the support member; and wherein the third radial distance is substantially the same as the first radial distance.
 6. The clot treatment device of claim 5, further comprising: a plurality of fourth clot engagement members positioned about the circumference of the distal portion of the support member, wherein, in the deployed state, individual fourth clot engagement members extend radially outwardly with respect to the support member and have a curved portion that includes a fourth radially furthest apex that extends a fourth radial distance from the support member; and wherein the fourth radial distance is substantially the same as the second radial distance.
 7. The clot treatment device of claim 6 wherein: the first clot engagement members are positioned at a first location along the length of the support member; the second clot engagement members are positioned at a second location along the length of the support member that is different than the first location; the third clot engagement members are positioned at a third location along the length of the support member that is different than the first and second locations; the fourth clot engagement members are positioned at a fourth location along the length of the support member that is different than the first, second, and third locations.
 8. The clot treatment device of claim 1, further comprising: a plurality of third clot engagement members positioned about the circumference of the distal portion of the support member, wherein, in the deployed state, individual third clot engagement members extend radially outwardly with respect to the support member and have a curved portion that includes a third radially furthest apex that extends a third radial distance from the support member; and wherein the third radial distance is different than the second radial distance and the first radial distance.
 9. The clot treatment device of claim 1, further comprising: a plurality of third clot engagement members positioned about the circumference of the distal portion of the support member, wherein, in the deployed state, individual third clot engagement members extend radially outwardly with respect to the support member and have a curved portion that includes a third radially furthest apex that extends a third radial distance from the support member; and wherein, in the deployed state, individual curved portions of the third engagement members project radially outwardly relative to the support member in a curve that has a distally extending section which defines a distally facing concave portion, and wherein the curved portion of individual third engagement members further includes an end section that curves radially inwardly from the distally extending section.
 10. A clot treatment device for treating an embolism within a blood vessel, the clot treatment device moveable between a low-profile undeployed state and a deployed state, the clot treatment device comprising: a support member configured to extend through a delivery catheter, wherein the support member has a proximal portion and a distal portion; a plurality of first clot engagement members positioned about the circumference of the distal portion of the support member, wherein, in the undeployed state, individual first clot engagement members are linear and have a first length; a plurality of second clot engagement members positioned about the circumference of the distal portion of the support member, wherein, in the undeployed state, individual second clot engagement members are linear and have a second length that is less than the first length; wherein, in the deployed state, the individual first and second clot engagement members project radially outwardly relative to the support member in a curve that has a proximally extending section which defines a proximally facing concave portion, and wherein the clot engagement members are configured to penetrate clot material along an arcuate path and hold clot material to the clot treatment device.
 11. The clot treatment device of claim 10 wherein the curve further includes an end section that curves radially inwardly from the proximally extending section.
 12. The clot treatment device of claim 10 wherein, in the undeployed state: individual first clot engagement members are positioned parallel to the support member; and individual second clot engagement members are positioned parallel to the support member.
 13. The clot treatment device of claim 10, further comprising: a first hub positioned around the support member at a first location; and a second hub positioned around the support member at a second location spaced apart from the first location along the support member; wherein— individual first clot engagement members extend distally from the first hub in the undeployed state, wherein a proximal portion of the first clot engagement members are integral with the first hub; and individual second clot engagement members extend distally from the second hub in the undeployed state, wherein a proximal portion of the second clot engagement members are integral with the second hub. 